JP2007098410A - Spot welding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spot welding machine capable of performing a welding without leaving welding traces and without soiling the top end of a welding tip by interposing a conductive continuous tape between the welding tip for performing the pressing conduction of a work such as a metallic material and a work W to be welded. <P>SOLUTION: In the spot welding machine, a welding gun having a welding tip 11 on the top end thereof is rotatably supported by a supporting arm 30 to perform the pressing conduction of a work W. The spot welding machine has a continuous tape 15 to be interposed between the welding tip 11 and the work W, a reel 152 for winding the continuous tape 15, a click member 42 to be engaged with the reel 152 at the tip reel 152, and an elastic spring 43 to be interposed between the click member 42 and the supporting arm 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spot welder, and more specifically, a conductive continuous tape is interposed between a welding tip for applying pressure to a material to be welded such as a metal material and the material to be welded, so that no post-welding remains. The present invention relates to a spot welder that can weld without welding the tip of the welding tip.

  Conventionally, when welding materials to be welded such as metal plates, such as rolled steel plates, aluminum and its alloy materials, and Zn-plated steel plates, at least two or more materials to be welded are stacked, and the upper and lower electrodes are sandwiched, Spot welding is used in which welding is performed by pressurization and energization to form a nugget for welding.

  In addition, this spot welding can be done in one spot in a few seconds, and once the welding conditions are set, it can be easily welded even by an amateur or a robot, and stable welding nuggets and joint strength can be obtained. It is used as a joining means in so-called sheet metal processing.

  In addition, while having such a wide application, spot welding is a chromium steel electrode usually used for spot welding of rolled steel plates used in automobiles and the like because of its electrical conductivity and mechanical strength. On the other hand, spot welding of aluminum materials, aluminum alloy materials, and Zn-plated steel sheets significantly shortens the life of the chrome copper electrode, increases the dressing strength, and increases the time required for it. It is a drawback.

  That is, the electrode life is the number of hit points at which a welded portion having a predetermined required performance is obtained continuously for each dressing. If a spot is hit beyond this number of hit points, the diameter and tensile shear strength of the hit nugget will be below the specified values. If the number of hit points is exceeded, an alloy layer of the electrode and the material to be welded is formed at the tip of the electrode, and this is transferred to the welded portion, so-called pickup is generated in which the appearance is impaired. Due to the pickup, the electrode may be welded to the coated welding material and cannot be removed.

  By the way, in the assembly line of automobiles, since it is spot welding of rolled steel plates, the electrode life is long and it is not necessary to consider this problem so much. However, in general, metal processing includes spot welding of aluminum or aluminum alloy materials. The electrode life of this spot welding is very short, and even in the case of a Zn-plated steel plate, the electrode life is considerably short. This problem cannot be avoided in general spot welding of metals.

  In view of the above, in a material having a short electrode life, such as an aluminum material, an aluminum alloy material, or a Zn-plated steel plate, as described in JP-A-61-159288, an electrode between the aluminum material and the aluminum alloy material is used. There has been proposed a welding method in which a more conductive insert material is interposed.

  In this welding method, since the insert material interposed between the two materials to be welded is highly conductive, the welding heat can be quickly removed, and the temperature rise at the contact portion with the material to be welded is suppressed. Therefore, the penetration of the welded material in the thickness direction can be made shallower, cracks on the back of the weld can be prevented, and the electrode life can be extended.

  However, since the insertion of the insert material cannot be performed every time the spot is welded, it must be performed at regular intervals, and a large jig device is required to automate the insertion itself. It is not always reasonable.

  By the way, in the automobile industry, recently, plated steel sheets such as Zn and Zn alloys have been used instead of rolled steel sheets, and aluminum materials and aluminum alloy materials have been used for weight reduction. . When this material is used, unlike a rolled steel sheet, when spot welding is performed, Zn or a Zn alloy having a low melting point is first melted and welded to the electrode by welding heat between the electrode and the plated steel sheet. Also, it may be made of electrode copper or copper alloy, and these molten metals alloy with copper and the like, and an alloy or alloy layer adheres to the tip of the electrode and adheres to the surface of the welded material during welding. The indentation (that is, the weld mark) is contaminated. Furthermore, this alloy or alloy layer moves to the molten surface of the material to be welded and the electrode is consumed. This electrode consumption is large at the center, and the tip of the electrode is deformed and becomes concave. Along with this, the nugget diameter and tensile shear strength of the welded portion decrease. This reduces the electrode life.

  For this reason, the electrode is cut or polished, and the tip shape is dressed again into a regular shape. However, it is not preferable if it is necessary to dress frequently. Especially in the case of a mass production line, the dressing is stopped and this is not preferable from the viewpoint of productivity.

  In short, among the electric welding using electric energy, spot welding is a method in which at least two or more materials to be welded are overlapped, sandwiched by upper and lower electrodes, pressed and energized to form a spot nugget and joined. It is said that it is the most suitable welding method for rolled steel plate, which is said to be thin compared to electric arc welding that requires a filler metal. It is a welding method that is also used for welding alloy materials, Zn-plated steel plates, and chemically treated steel plates.

  Although it is spot welding with such advantages, since the chrome copper electrode is a mechanism that directly participates in the pressurization energization of the material to be welded, there is an electrode life, which is larger for the material to be welded. If there is a width and the electrode exceeds this life, an alloy layer is formed at the tip of the electrode by the fusion of the electrode and the material to be welded, and a phenomenon such as so-called pick-up occurs. The alloy melts and welds with the electrode, the electrode is consumed, the shape of the electrode tip changes, and dressing is absolutely necessary to return the tip shape to the normal shape.

  Therefore, the present inventors first conducted the upper and lower welding electrodes sandwiching the material to be welded from above and below, with the lower welding electrode being flat and conductive on the surface of the upper welding electrode configured in a rod shape. A spot welding machine was proposed that can be welded with the welded material set on the table-like electrode. (Japanese Patent No. 3445636) The welding tip attached to one end of the upper bar-shaped welding electrode in this welding machine can be driven freely on the table-shaped electrode and can be used in either a vertical position or a horizontal position. It is.

  This table-type spot welder can be used by using the rod-shaped electrode itself when the upper rod-shaped electrode is used in the horizontal orientation, and the tip of the welding tip uses a boosting mechanism called a lever mechanism. The structure is such that a high downward pressure can be applied to the workpiece, and in addition to this, the structure is such that the welding heat can be quickly removed by the table-like electrode.

  That is, in this spot welding machine, the lower welding electrode is formed in a table shape, and a cooling passage is formed over the entire surface of the table welding electrode, so that the cooling capacity is greatly enhanced. To put it flatly, by improving the electrode structure of the lower welding electrode among the pair of upper and lower welding electrodes, the cooling capacity of the welding electrode is greatly increased, and the low melting point metal in the aluminum material or the plated steel sheet being welded This prevents the melting and pick-up caused by it from extending the electrode life and minimizing dressing.

  That is, in the lower table-like electrode, the flat and wide surface is energized everywhere, and when it is pressurized by the corresponding upper rod-like electrode, it is the place where the pressure is supported. The portion becomes a spot electrode (spot electrode) and welding is achieved.

  Accordingly, since the entire flat surface of the table-like lower electrode is configured to be a spot electrode at any place, the cooling water smoothly flows over the entire surface. For this reason, even if a large amount of welding heat is generated during welding, heat is extracted from the table-type electrode having a large cooling capacity close to infinity. Thus, the temperature of the surface of the table-like electrode or rod-like electrode is reduced, and even if the material to be welded is a Zn-plated steel plate or aluminum material, it hardly melts, and the electrode life is also reduced without generating a pickup. improves.

However, the table-type spot welder previously proposed has the upper welding electrode at the tip even though the lower welding electrode is entirely made of copper or its alloy and is extremely large as a cooling source. Since it is composed of a rod-shaped electrode with an electrode tip on it, when it is used repeatedly, an alloy with copper adheres to the tip, and furthermore, the cooling capacity lacks balance between the upper and lower welding electrodes. Thus, the adhesion of the deposit during welding is shifted to the upper welding electrode, and this tendency tends to appear particularly when chemical conversion treatment steel plate, bond treatment steel plate, parkerizing steel plate or the like is welded.
Japanese Patent Laid-Open No. 61-159288 Japanese Patent No. 3445636

  An object of the present invention is to solve the above-described drawbacks. Specifically, one electrode is configured as a plate-like electrode having a large area among a pair of electrodes that sandwich a work piece and pressurize and energize, while an upper bar shape. A table-type spot welding machine is proposed in which a conductive tape is interposed in an electrode, and the conductive tape can be sequentially fed in conjunction with the welding operation of the upper welding electrode.

  That is, the present invention provides a welding gun having a welding tip at the tip, and supports the welding gun to be welded by the welding tip by rotatably supporting the welding gun at the lower end of the supporting arm and applying a pressure to the workpiece to be welded by the welding tip. In a spot welding machine having a lever mechanism that energizes over time, a continuous tape interposed between the welding tip and the material to be welded and a winding reel for winding the continuous tape are provided. And a click member for connecting the pawl wheel to the take-up reel and for feeding at least one pawl of the pawl wheel, and the click member is attached to the support arm via a spring member. Features.

  Since the continuous tape is interposed in this way, the life of the welding tip is greatly improved, and it can be welded without any trouble even in the welding of an aluminum material or a surface-coated steel plate, and the continuous tape is made of copper or its alloy material. Since these are used and the investment funds are recovered as expensive scraps, there is no economic problem.

  Then, it is as follows when it shows more concretely through the place shown in drawing about the structure which is the above solution means, its effect | action, and its effect.

  FIG. 1 is a front view showing a part of a spot welder according to one embodiment of the present invention in cross section.

  FIG. 2 is a cross-sectional view from the direction of arrows AA in FIG.

  FIG. 3 is an explanatory diagram of one usage mode of the spot welder of FIG.

  FIG. 4 is an explanatory view of another usage mode of the spot welder of FIG.

  FIG. 5 is an explanatory view showing, in section, a part of a continuous tape feed mechanism in a spot welding machine according to one embodiment of the present invention.

  FIG. 1 is an explanatory view showing a part of the structure of a spot welder according to one embodiment of the present invention. Reference numeral 100 denotes a spot welder according to one embodiment of the present invention. As will be described later, this spot welder 100 is a plate-like table in which at least the lower welding electrode 20 of the upper and lower welding electrodes 10, 20 is made of a conductive material such as copper or copper alloy. It consists of a shape electrode. When this table-like electrode is made of copper or a copper alloy material, a chromium-copper alloy plate-like material is preferable in order to maintain mechanical strength without impairing electrical conductivity. Moreover, in order to harden only the surface and remove a welding trace, the work hardening layer can also be provided on the surface by work hardening the surface by plastic working. Further, a cooling water passage (not shown) through which cooling water flows and cools inside the lower electrode 20 as a plate-like electrode, that is, a table-like electrode, is provided over the entire surface or almost the whole. For this reason, a part of the surface of the plate-like lower electrode 20 is locally exposed to welding heat. In particular, even when the temperature is higher than 500 ° C./the table-type electrode flows through the cooling water passage over the entire surface. The cooling capacity is extremely high, and the cooling capacity is extremely large, and a considerable amount of welding heat flows preferentially toward the lower welding electrode 20 as compared with the upper bar-shaped welding electrode 10, There is no sudden temperature rise at the contact surface.

  That is, in the spot welder 100, the lower electrode 20 is made of a plate-like or table-like electrode plate, whereas the upper electrode 10 is made of a rod-like welding gun. As shown in FIG. 1, the upper electrode 10 moves up and down in the vertical direction, and is spot-welded with the work piece W between the lower electrode 20 and the upper electrode 10.

  As described above, the upper electrode 10 is spot-welded with the workpiece W sandwiched between the lower electrode 20 and has a welding tip 11 at the tip, and is composed of a shank 12 and a holder 13. Configured as a welding gun. The welding gun 10 is arranged in a horizontal posture, and is supported by a support arm 30 so as to be movable up and down at a pivot 31, and the welding gun itself of the upper electrode 10 forms a lever that rotates around the pivot 31. ing. Therefore, the rod-like upper electrode 10 works as a booster mechanism on the lower electrode 20 whose entire surface functions as an electrode, and at the time of welding, a desired welding point is obtained with the work W being placed on the lower electrode 20. After moving the welding tip 11 to the point, the workpiece W is sandwiched between the lower electrode 20 and the desired welding points are sequentially spot-welded in the form of an arc.

  The support arm 30 for rotatably supporting the upper electrode 10 may be provided with a cantilever beam (not shown) protruding on the lower electrode 20 and supported by being suspended via the cantilever beam. it can. Thus, even if it does not comprise a support mechanism, it can also be supported by a gate type support | pillar other support means.

  On the other hand, even if the lower electrode 20 configured in a plate shape or a table shape is not composed entirely of a conductive material, only the surface thereof is composed of, for example, copper or an alloy thereof, and cooling water is circulated in the planar direction inside. A cooling water passage (not shown) is provided. Welding heat is taken by the cooling water flowing through the cooling passage extending over this wide space, so that the contact surface between the workpiece W and the electrode can be prevented from melting and contamination can be prevented.

  Generally speaking, the role of the upper and lower electrodes in spot welding is to supply a large current to the weld and apply a high pressure. On the other hand, when the viewpoint is changed, each of the electrodes 10 and 20 quickly removes the welding heat and cools the surface of the welded portion. From the viewpoint of weldability, this aspect can be most emphasized practically. That is, in both the electrodes 10 and 20, the welding heat is a kind of heat removal means, which is carried away by the cooling water. From this aspect, the electrodes 10 and 20 are required to have a high thermal conductivity. It is necessary to have a structure in which as much cooling water as possible can flow structurally. In this regard, in the table-type spot welding machine proposed by the present inventors, the plate electrode 20 serving as the lower electrode has a plate shape with a large area. Therefore, it can be configured in a structure that can sufficiently supply cooling water to the inside. In particular, since it is made of copper or its alloy with high thermal conductivity, most of the welding heat can be accepted. Due to the high thermal conductivity, the welding heat is smoothly given to the cooling water, and the surface temperature of the welding tip is Without being increased, the deformation of the welding tip is not accelerated, and picking up by alloying with the material to be welded does not occur.

  The lower table-type plate-like electrode 20 is made of copper or a copper alloy and is sufficiently cooled even when a hardened layer is formed by, for example, work hardening of the copper or copper alloy, so that the hardening is restored. There is nothing.

  Copper or an alloy thereof is a face-centered cubic lattice as a structure. This face-centered cubic lattice is much easier to slide than those of body-centered cubic lattices such as iron and steel. That is, when an external force is applied to copper or a copper alloy having a face-centered cubic lattice, a transition generated in a part of the lattice is transmitted along the sliding surface, and metal atoms in the crystal lattice move, which is said to be easy to process. Beyond this sliding area, the slip accumulates in the lattice, which disturbs the transition and hardens. It is also a characteristic of copper that this degree of hardening is extremely high.

  This feature can be used effectively by increasing the cooling capacity by making the lower electrode 20 into a table or plate. That is, since the welding heat is quickly removed by the cooling water, the temperature of each contact surface of the electrodes 10 and 20 does not increase. For this reason, work hardening is not tempered and softened.

  Further, the upper welding electrode 10 is configured as a rod-shaped welding gun with respect to the table-type electrode of the lower welding electrode 20, and is composed of a tip 11, a shank 12, and a holder 13, which are connected to each other. Thus, it can be configured as a rod-shaped welding gun, or can be configured as a single unit without a joint, and can also be configured as an integrated welding gun. When the welding gun 10 is configured in a bar shape and is supported rotatably at a pivot point 31 by a support arm 30, a lever mechanism can be configured.

  If comprised in this way, the welding tip 11 of a front-end | tip uses a lever mechanism, and can pressurize by raising a pressurization thing between the to-be-welded object W between the plate-shaped table-like electrodes 20 of a lower part, and a spot. Can be welded.

  In addition, the welding gun used as the upper welding electrode 10 can be used by any means as long as it is configured in a rod shape. In order to improve the cooling performance of the welding tip 11 at the tip, it is preferable to form a single piece without a joint. That is, with this configuration, even if the water pressure of the cooling water is increased, there is no seam portion, so water does not leak from that portion, and the cooling performance can be greatly enhanced. In the example shown in FIG. 1, the welding tip 11, the shank 12, and the holder 13 are integrally joined together as a single piece. When manufacturing, these can be cast as one.

  In other words, the welding tip 11 at the tip of the rod-shaped welding gun 10 is a portion that directly contacts the equipment or member W to be welded and is pressurized and energized for welding. For this reason, the welding tip 11 is conventionally comprised so that it can isolate | separate as a consumable. However, if it is configured to be separable in this way, a seam remains in the portion, the contact resistance increases, and seizure often occurs, which is also a major drawback in spot welding. From this point of view, in the present invention, it is preferable that the tip 11 is constituted by being continuously connected to the shank 12 seamlessly.

  More specifically, it is the welding tip 11 at the tip that directly contacts the workpiece W as the upper welding electrode 10 and participates in the welding. The welding tip 11 is warmed to the highest temperature, and the surface becomes dirty and worn by a pickup or the like. In particular, the tip of the welding tip 11 seems to have reached 600 to 900 ° C. even when viewed from the temperature of the cooling water. When the high-temperature welding tip is further heated by the resistance of the seam, the seam often seizes, and even if only a few hundred strike points are hit, it cannot be removed due to seizure.

  In addition, the seam is repeatedly heated and cooled, and the thermal expansion and contraction are repeated, so that a gap may be formed, and the cooling water may leak from there. Furthermore, when the material to be welded is an aluminum material, a plated steel plate, or other chemical conversion treated steel plate instead of the rolled steel plate, the replacement frequency of the welding tip 11 is increased, and this replacement takes a lot of trouble. In any case, it is preferable that the welding tip 11 is integrated and is freed from such a problem. In this regard, in the present invention, as will be described later, it is preferable that a conductive tip is interposed on the outer periphery of the welding tip 11 so that the welding tip 11 can be configured integrally without a seam.

  Although the upper welding electrode 10 is not necessarily configured integrally, it can be configured by separating the tip welding tip, shank, and holder as long as it can be used as a bar-shaped lever. It is also preferable that the holder 13 and the holder 13 are constructed as one piece without a joint.

  That is, in the case of the welding gun 10 in which the respective parts are continuously and integrally formed as described above, the cooling water passage 14 is provided seamlessly along the central axis, and the cooling water passage 14 is provided from the holder 13. It is possible to communicate with the welding tip 11 through the shank 12 as a single piece.

  Further, the forward path 141 and the return path 142 of the cooling water passage 14 can be configured to be continuous, and the cooling water flowing in from the inflow port 143 is jetted close to the surface of the tip welding tip 11 to cool the welding tip 11, It is discharged from the outlet 144 through the return path 142.

  Such a cooling water passage 14 is formed integrally with the welding gun 10 itself, and the cooling water passage 14 reaches the tip 11 at the tip from the inlet 143 along the central axis. Thus, it can be sprayed directly close to the outer periphery of the chip 11 and can be cooled effectively. For this reason, even if the tip 11 is exposed to high welding heat, a considerable amount of welding heat can be removed by the cooling water reaching the tip 11.

  Further, the flow of the cooling water has no seam between the portions of the welding gun 10, so that there is no leakage at all, and the dissipation of welding heat is promoted.

  Next, in the welding gun 10 configured as described above, the conductive continuous tape 15 is arranged along at least the outer periphery of the tip 11 and the shank 12. When the conductive continuous tape 15 is provided, it can be implemented in any manner. However, a rewinding reel 151 and a winding reel 152 are provided between the welding guns 10, and this rewinding reel is provided. The intermittent feed mechanism 40 including the pawl wheel 41 and the click member 42 is interlocked with the reel 151, and the conductive continuous tape 15 is sequentially fed by the welding gun 10 for each unit welding (that is, one hit point) as described later. Configure as follows.

  Further, the guide passage 16 extends in the axial direction on the outer periphery of the tip 11 and the shank 12. The guide passage 16 guides the conductive continuous tape 15 rewound by the rewinding reel 151 along the welding gun 10, and thus the conductive continuous tape 15 is interposed. When welding, the tip 11 does not directly contact the workpiece W to be welded, so that the welding can be smoothly performed without fusing with the workpiece W. In particular, since the welding points to be welded are welded by sequentially feeding the conductive continuous tape 15, spot welding can always be performed with a new contact surface. Naturally, the welding tip 11 is not deformed and there is no need for dressing.

  More specifically, spot welding is performed by pressurization and energization by the tip 11. If the tip 11 is brought into direct contact and is repeated, the surface of the tip 11 is locally melted and contaminated, and the surface of the material to be welded is left with a welding mark or the like, and the quality of the welded portion is deteriorated. to degrade. In order to remove it, the inside of the chip 11 is cooled from the inside, and a structure that can cool as close to the outer surface of the chip 11 as possible is desirable. In this regard, when the welding gun 10 is formed integrally from the tip 11 to the holder 13, the internal cooling water passage 14 reaches the vicinity of the outer surface of the tip 11 seamlessly (in particular, about 5 to 7 mm), where it is cooled. Water can be jetted. For this reason, the chip | tip 11 can be cooled effectively. Furthermore, since it is integrated seamlessly, the cooling water does not necessarily leak and the water amount and flow rate can be freely adjusted, and the cooling effect can be enhanced from this aspect.

  However, the ability to cool to the outer peripheral surface of the welding tip 11 is that a large amount of welding heat is generated for each welding (as described above, the contact surface of the welding tip 11 is about 500 ° C. to 900 ° C. due to this heat. Can be quickly carried away by the cooling water, and favorable conditions can be set for welding. However, contrary to this, even if preferable conditions are obtained, there is a limit in making the chip 11 thin. That is, when a high pressure is applied, the welding life is shortened due to deformation over time or contamination of the outer surface, and dressing is repeated.

  From this point, the outer periphery of the electrode tip 11 is covered with the conductive continuous tape 15, and every time welding is performed using the welding gun forming the upper electrode 10, that is, for each unit welding, the conductive continuous The tape 15 is sent intermittently or intermittently so that a new surface of the conductive continuous tape 15 is always in contact with one welding point so that welding can be performed.

  If comprised in this way, in addition to being freed from work such as dressing or replacement of the electrode tip 11, there is almost no trace of welding left in contact with the conductive continuous tape 15 for welding, Since a substantial portion of the welding heat generated during welding is carried by the conductive continuous tape 15 and removed, the cooling capacity is further improved, and the welding tip 11 is always cooled, at most 200 to 300. It can be maintained at about ℃.

  When the conductive continuous tape 15 is interposed in the welding tip 11 in the upper electrode composed of the rod-like welding gun as described above, the outer periphery of the welding tip 11 and the shank 12 extends along the axial direction as shown in the figure. Therefore, it is preferable to extend the guide passage 16 and to integrate the conductive continuous tape 15 and the welding gun 10 together. That is, as shown in FIG. 5, the conductive continuous tape 15 guided along the guide path 16 has less contact resistance with the conductive continuous tape 15 between the outer surface of the chip 11. It is to follow. When the guide passage 16 is the welding gun 10 in which the tip 11, the shank 12 and the holder 13 are integrally formed, at least the outer periphery of the shank as an integral part thereof is a flat groove 161 having a rectangular cross section along the axial direction thereof. And the conductive continuous tape 15 is fed using the flat groove 161 as a guide. In order to seal the flat groove 161, a pair of sealing rings 162 are provided. Further, the tip of the chip 11 forms a pair of flat surfaces 111 and is brought into contact with the flat surfaces 111 so that a conductive continuous tape is formed. -Wrap the loop 15.

  In addition, the conductive continuous tape 15 needs to be sent sequentially for each welding. For this purpose, an unwinding reel 151 and a winding reel 152 around which the conductive continuous tape 15 is wound are provided with the shank 12 interposed therebetween. The winding reel 152 is configured to rotate intermittently or intermittently, is connected to the intermittent feed mechanism 40, and is connected to the support arm 30 via the intermittent feed mechanism 40. The intermittent feed mechanism 40 can be configured electrically without being mechanically configured as long as the object can be achieved, but the illustrated example is one of mechanically configured.

  That is, as shown in FIG. 2, the intermittent feed mechanism 40 is connected to a winding reel 152 and has a toothed wheel 41 having a sawtooth-shaped pawl indicated by a one-dot chain point, and a click ( click) 42, and the pawl of the pawl wheel 41 is formed in a sawtooth shape. When at least one pawl is fed, the pawl wheel 41 is rotated at a unit pitch and intermittently wound. It is configured such that it is wound around a reel 152 and a conductive continuous tape 15 is fed. As shown in FIG. 1, the click member 42 is configured as a rod-shaped arm, and a click 421 such as a saw tooth is provided at the tip of the click member 42, and the click 421 is configured to mesh with the feed pawl of the pawl wheel 411. Yes. On the other hand, the rear end of the click member 42 is attached to the side surface of the support arm 30 through an elastic spring 43 as a kind of quick return mechanism. When the handle 50 welded to the welding gun 10 is pushed down, the click member 42 is paved as shown in FIG. When the wheel 411 is rotated counterclockwise to wind up the continuous tape 15 and the handle 50 is pushed up, the pawl of the pawl wheel 41 can be welded to the new surface of the continuous tape 15 that has been fed without slipping. .

  For this reason, the welding gun of the upper electrode 10 is lifted and rotated upward (counterclockwise direction) around the pivot point 31, and the welding tip 11 at the tip of the welding gun 10 descends and contacts the surface of the workpiece W for welding. enter. At this time, the pawl of the pawl wheel 41 has a sawtooth shape, and the click 421 and the pawl of the pawl wheel 41 do not mesh with each other when the welding tip 11 is lowered (when rotating counterclockwise). When the welding gun 10 is rotated in the hour hand direction after completion of one spot welding, the click member 42 is quickly returned to the original state by the elastic spring 43, and at this time, the click 421 is clicked on the pawl 411 (saw tooth). Engage with each other and feed unit pitches, and take up the conductive continuous tape 15 sequentially unit pitches, and the next welding can be performed under completely new conditions.

  The rewinding reel 151 and the winding reel 152 are preferably integrated and detachably attached to the welding gun 10. That is, as shown in FIG. 2, the winding reel 152 and the unwinding reel 151 are integrated via a connecting plate 153, and this connecting plate 153 is attached to the welding gun 10 via a tightening screw 154. Is attached to the welding gun 10 with a fastening screw 154 so that it can be removed and welded when the material to be welded is a rolled steel plate.

  In short, the pawl wheel 41 is fed by the click member 42, for example, in the counterclockwise direction, winds the conductive continuous tape 15 by a unit pitch, and is connected to the lever movement of the welding gun 10 in this continuous state. Tape 15 feed can be achieved.

  As described above, the spot welder according to the present invention is a spot welder in which an upper electrode is formed by interposing a conductive tape in a rod-shaped welding gun, and welding is always performed with an electrode having a new contact surface. In addition to welds and spots that can be welded and excellent in quality, such a welding machine is not necessarily a table type, but any apparatus having a mechanism for raising and lowering the welding tip can be used. It can also be applied to things. Furthermore, in the above description, the example in which the lower electrode is constituted by the table-like electrode is mainly shown, but the present invention can also be applied to a spot welder in which the lower electrode is constituted as a rod-like electrode.

It is a front view which shows a part of spot welding machine which concerns on one Example of this invention in a cross section. It is sectional drawing from the arrow AA direction of FIG. It is explanatory drawing of one usage condition of the spot welder of FIG. It is explanatory drawing of the other usage condition of the spot welder of FIG. It is explanatory drawing which shows a part of continuous tape feed mechanism in the spot welding machine which concerns on one Example of this invention in a cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Welding gun 11 Welding tip 15 Continuous tape 20 Table-shaped electrode 30 Support arm 42 Click member 43 Elastic spring 100 Spot welding machine 151 Rewinding reel 152 Winding reel

Claims (6)

A welding gun provided with a welding tip at the tip, and this welding gun is rotatably supported at the lower end of a support arm, and the welding gun is used to apply a pressure to the material to be welded by the welding tip to energize it. In a spot welder comprising a lever mechanism
A continuous tape interposed between the welding tip and the material to be welded and a winding reel for winding the continuous tape are provided, and a pawl is connected to the winding reel. On the other hand, a spot welding machine comprising a click member for feeding at least one claw of the pawl wheel and attaching the click member to the support arm via a spring member.   2. The spot welding machine according to claim 1, wherein the lower electrode corresponding to the welding tip is a plate-like table electrode.   2. The spot welder according to claim 1, wherein the lower electrode corresponding to the welding tip is a rod-shaped table electrode.   The winding reel is provided on the welding gun, and a rewinding reel for rewinding the continuous tape corresponding to the winding reel with the welding gun interposed therebetween is provided. The spot welder according to claim 1, 2, or 3.   The spot welder according to claim 1, 2, or 3, wherein a claw provided on the claw wheel is configured in a sawtooth shape, and a click meshing with the claw is provided at a tip of the click member. The said winding reel and the said rewinding reel are comprised integrally through a connection board, and this connection board is attached to the said welding gun so that attachment or detachment is possible, The spot welder according to 3, 4, or 5.

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